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(No Model.) 2 Sheets-SheeI: 1. J. BAIRD. STEAM ENGINE DRIVING GEAR.

No. 425,971. Patented Apr. 22, 1890. I

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(No Model.) 2 SheetsSheet 2. J. BAIRD. STEAM ENGINE DRIVING GEAR.

Patented Apr. 22,1890.

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UNITED STATES PATENT OFFICE.

JonN BAIRD, on NEW YORK, N. Y.

STEAM-ENGINE DRIVING-GEAR.

SPECIFICATIONforming part of Letters Patent No. 425,971, dated April 22, 1890.

Application filed December 17, 1889. Serial N0.334,018. (No model.)

To all whom, it may concern.-

Be it known that I, JOHN BAIRD, mechanical engineer, of the city, county, and State of New York, have invented certain new and useful Improvements in Steam-Enginel)riving-Gear and I do hereby declare that the following, taken in connection with the drawings, is a full, clear, and exact description thereof.

These improvements relate to the structure of compound engines chiefly useful for driving the paddle-wheels of river and bay steamers; but they may be employed for other purposes; and the leading idea of the invention is the application of the power derived from several cylinders to a single crank shaft through the intervention of a single connecting rod and crank and a rock-shaft which derives its motions from all the cylinders and actuates the crank by its torsional strain.

The drawings are little more than sketches; but they are sufficient to enable those conversant with steam-engines to understand my invention and build an engine in accordance therewith.

I11 the drawings, Figure 1 is a side elevation of the central cylinder and its connections with the crank shaft. Fig. 2 is an end elevation of the rock-shaft and its arms, also the crank and crank-shaft. Fi 3 is a plan of parts of the engine, showing the air-pump and condenser. Figs. l and 5 are respectively side and front elevations, on a larger scale, of the preferred form of central rockshaft arm. Fig. 6 is also a side elevation.

In the drawings, or represents a rock-shaft firmly supported in proper bearings near the bottom of the ship.

Z) I) b are three cylinders, which are to be provided with pistons, side pipes,valve-chests, and valves of any usual proper construction, and with valvegear of some proper kind for actuating the valves. The crossheads are represented. at c c c, the pistonn'ods at (Z (Z, the links of the central cylinder at f f, the central rock-shaft arm at g g, and the side rock-shaft arms at 71 h. All these rock-shaft arms are firmly keyed or otherwise secured to the rock-shaft, so that they move in unison or as a whole. The connecting-rod is shown at c, the crank at j, and the erank shaft at 70, supported in any usual manner and by appropriate framin By noticing the drawings it will appear that the highn'essure cylinder is at one side of the structure as a whole, the intermediate in the center, and the low-pressure at the other side. This arrangement is the most convenient, but not essential. If a quadruple expansion be desired, the best plan for securing this result will be to apply a fourth cylinder tandem fashion behind the central cylinder. The connections serving to carry the exhaust from one cylinder to the pressure side of the succeeding cylinder may be constructed in any usual way; and two cylinders onlymaybe connected with the rock-shaft, instead of three, as shown in the drawings. The cylinders may be of various strokes, instead of a uniform stroke, as shown in the drawings, provided the link-pins on the rock-shaft arms are so arranged that each is at the proper distance from the center of motion of the roek-shaft. All the cylinders in a compound engine may then be of the same diameter, but of varying strokes. I intend also at times to locate the rock-shaft above the connecting-rod pin and link-pins, so that the rock-shaft arms will hang below the shaft, instead of projecting upward from it; but I much prefer the precise arrangement shown in the drawings.

The operation of the structure is obvious; but it may perhaps be well to state it as follows: All the pistons move at the same time in the same direction. All of them simultaneously and jointly rock the rock shaft, and the power obtained from all the cylinders is applied to drive the crank through the single connecting-rod by the torsional strain on the rock-shaft. The throw of the crank may be made greater than the stroke of the piston by setting the connecting-rod pin on the beam farther from the center of motion of the rockshaft than the distance between the link-pin and the same center of motion, as indicated in Fi 6, which figure also shows 110w the airpump may be worked from the rock-shaft by means of a short arm m, a link 0, abell-crank p, and links q, connecting one arm of the latter with the rod of the air-pump bucket. I int-end also, if desired, to use cylinders in which the exhaust from each proceeds directly to the condenser or open air, instead of passing into another cylinder.

I prefer to make the central rock-shaft arm with a slot in it, or of two Substantially parallel arms, prongs, or side pieces, as represent-ed in Figs. 4 and 5, so that the connecting-rod may be applied to the pin 9 between the pieces and the links from the crosshead to the pins x 00, one outside of each piece. As nnderthis construction the pins am; will. have but a comparatively short length of bearing in the arms, I project the connecting-rod pin g outside of the arms and unite the projecting ends of the pins by means of braces, stay-rods, or links 2. These links also convey the strain on the link-pins in a direct line to the connecting-rod pin. I intend at times to arrange the cylinders horizontally, but prefer the inclined arrangement shown in the drawings.

I claim as my invention- 1. The combination of two or more cylinders, a rock-shaft, rock-shaft arms secured at different intermediate points thereon, connechereunto subscribed my 11am 0.

OHN BAIRD.

Witnesses:

JOHN STUART BAIRD, A. J'. BAIRD. 

